Hi, new user and new owner of 78 cj7. First jeep and love the vehicle--the wiring is another story. Jeeps runs great and has lots of upgrades including efi. Have noticed two issues: battery drains at night and after running around town 30 mins two nights in a row, the headlights will cycle on and off for a few min then operate fine.

I have read the great posts especially by Jeephammer and the gang but before I start tracing back all the issues I want to see if the basics are correct.

You can see there are extra relays but a few questions since posts say not to have anything directly to positive battery terminal. You can see former owner has added a relay for the efi that is connected directly to positive terminal and to alt.

A few dumb (likely) questions:
Q1: starter only has one wire to solenoid (far side) and no connection to the negative battery post, is that correct?
Q2: new alternator with main wire to solenoid and then two wires combined into one that goes to that extra efi relay. Correct?
Q3: solenoid has alt cable, and wiring harness on one end, then blue wire from harness on next terminal, then nothing, then black wire to starter. Correct? What is blank post for?
Q4: there is an extra module of wires that runs from efi relay and battery direct but just has unhooked wires. Is this the correct way to wire it?

If these are correct I can start tracing the drain and the light flickering issue ( would this have to do with heat since only occurs around town after 30 min)...

This is going to be tough unless you find someone with experience with that EFI. Do you have the model etc.?

The starter gets grounded through the block so as long as there is a good ground to the block you are fine there.

Not sure what relay you are talking about, that rectangular thing on the fender is a self resetting fuse, probably ~60A.

It looks like the alt is basically connected straight to the battery with ~#4, that is no good, there need to be a fuse somewhere. The may be some sort of fusible link under the heat shrink near the alt but who knows.

EFI wiring instructions likely said connect directly to the battery, I know MSD says that in their instructions.

The drain is difficult to say, follow the pos side around and see what it is connected to and start disconnecting things until the load goes away. A test light should work for showing what is taking a load, put it between the pos and the wire you disconnect. If it lights that is taking power.

Judging from all the heat shrink etc. it appears the PO did a decent job of the install. Just needs to be checked over.

Are the headlights connected through a relay? If so have you tried swapping it out?

1st is your alternator charging the battery? With the engine running a voltmeter should show something over 13 volts if it's actually charging.

If you have a drain when everything is shut down, to find it is fairly straightforward. Hook your amp meter up in series between your battery ground cable and the battery. By that I mean disconnect the negative battery cable and then hook the red lead to the battery cable and the black lead to the battery negative terminal.

Turn the meter on to measure amps. It should give some type of reading showing you how much current flow is going on. Most multimeters are rated to measure up to 10-15 amps. That's not much of a rating, but it's fine for checking parasitic draw off a battery.

Then just start pulling fuses one at a time till you see the amp draw disappear or drop significantly. Then you know what circuit to check. Now put the fuse back in. Then start disconnecting different electrical devices on that circuit to make the current drop again. Once you've done that then you've found the culprit.

Keep in mind that since the engine has EFI it will possibly still show a small amp draw normally. It will be very low, the EFI computer might be doing it. Not enough to drain the battery for awhile, like months.

Two items that will drain a battery overnight are the ignition coil or field circuit in the alternator. If either of those is on all the time it will do it. Or if a diode has failed in the alternator it will drain the battery too, plus the alternator won't charge the battery correctly.

For the intermittent headlight issue there is a breaker in the headlight switch. Sounds like it got weak. Good time to replace it or you could rewire the headlights and use relays to control them. Popular upgrade covered alot around the web. Dimmer switch on the floor is known to cause intermittent problems, but headlight switch is what I'd go after first based on your symptoms. Good luck!

Thanks for the start guys. It's an edelbrock pro-flo efi. It looks like that part is wired right from what I can tell except for the question of whether that self resetting fuse should be connected directly to the positive cable and the alternator?

The vehicle is showing over 13 volts. The alt is looks new.

The alt is connected to solenoid and at same terminal there is a wire directly connected to battery and one to the wiring harness. Opposite side to starter.

A quick check of the diodes in the alternator can be done with any voltmeter that can read AC volts. What you do is run the engine with the multimeter hooked up red lead to post on back of alternator, black lead grounded where you choose. If all is well with the diodes inexpensive multimeters will show a value of around 31 volts AC with some slight variation. Expensive meters will show 0 zero volts AC. If you have either value your diodes are good to go.

Battery voltage will vary with temp and specific gravity of the electrolyte. At rest with engine off, a healthy battery is around 12.6 volts when it's around 75-80 deg F.

The diode trio was the culprit in my overnight batt drain issue. Cheap part $5 or so but kind of a pain to replace...

Yup, the 13 volts implies it was bad. Should be seeing over 14 when running. When a diode shorts it draws the output down, when one blows, it drives the output up so if you see over 15v, the diode pack is also suspect.

I routinely see 13.6 volts on mine after it's started up and ran awhile. It varies based on the condition of the battery and how long the engine has been running since last start.

The voltage will also slightly differ from voltage regulator to regulator. It will also be a different reading from meter to meter and even the leads you are using. I'm happy if I see anything over 13.5 after things settle.

If you want to know if a diode is bad and eliminate it from your list of possibilities, I gave you the answer to that above.

Hi, new user and new owner of 78 cj7. First jeep and love the vehicle--the wiring is another story. Jeeps runs great and has lots of upgrades including efi.

1. Have noticed two issues: battery drains at night and after running around town 30 mins two nights in a row,

2. the headlights will cycle on and off for a few min then operate fine.

1. You need FIX what PO has done.
The smaller 'Red' wire to the battery needs to be attached to the battery cable side of the starter relay.

That wire MUST go to the 'Brass' post on the breaker,
And the 'Silver' or 'Steel' post on the breaker goes out to the accessory.

I can't tell in the picture if it's wired this way or not.

THEN...
You need to DISCONNECT either the positive or negative battery cable from the battery, and put a volt meter between cable and post.

This will let you track voltage drawn from battery with the key switch 'OFF'.
Start pulling fuses, disconnecting things until you find the drain,
Then address the drain issues.

Where I would start,
There *Should* be two wires (About 10 Ga.) connected to the starter relay battery cable post.

One should be the alternator 'BAT' terminal,
The other should be the feed to the headlights/fuse block.
This will tell you right away if the drain is under the dash or the alternator.

When alternator rectifiers fail, they drain batteries. Disconnecting a bad alternator will show you a significant drop in 'Drain' on the battery,
And the same is true when you disconnect the power feed to headlights and fuse block under the dash.
This will give you a direction to go with further testing...

2. Headlights draw power from the same 10 Ga. wire that powers the fuse block,
BUT ARE NOT connected to the fuse block.

All other lights have a fuse, but headlights have their own circuit breaker built into the headlight switch.

The 'ON/OFF' cycling of the headlights might be that breaker in the switch giving up,
Or it might be your headlights are drawing more current than the breaker can supply safely and the SELF RESETTING breaker is cycling to save your wiring...

If that is the case, there is probably a bad dimmer switch, pinched wire, over sized lights, ect. causing the breaker to cycle and save the wiring.

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Quote:

You can see there are extra relays but a few questions since posts say not to have anything directly to positive battery terminal. You can see former owner has added a relay for the efi that is connected directly to positive terminal and to alt.

Like I said, move the battery small wire connection to the starter relay, battery cable side,
And treat it like a third point of drain,
Unhook it with volt meter connected between battery post and cable to see if it's sucking your battery while the key switch is 'Off'...

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Quote:

A few dumb (likely) questions:
Q1: starter only has one wire to solenoid (far side) and no connection to the negative battery post, is that correct?

Starter relay depends on *IF*...
You have an automatic transmission or not.
Automatics have an isolated 'Ground' to the solenoid that is routed through the Neutral Safety Switch.
Not in 'Neutral' or 'Park', the engine won't crank.

Manual transmission starter relays don't have that isolated 'Ground' and connect to Battery Negative through the sheet metal.

An added dedicated 'Ground' to the bracket always helps with diagnostics and with starting, and isn't a bad idea if you are wiring anyway...
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Quote:

Q2: new alternator with main wire to solenoid and then two wires combined into one that goes to that extra efi relay. Correct?

NO!

Fuel injection computers can be incredibly picky about 'Line Voltage'!

AND...

NO WIRE SHOULD GO TO THE ALTERNATOR 'BAT' TERMINAL WITHOUT A FUSIBLE LINK OR FUSE!

You *Should* run the alternator 'Output' back to the battery cable connection at the starter relay (With a fusible link at the relay for the alternator wire),

AND THEN pick up power for the fuel injection at the starter relay battery cable connection.

That way, the fuel injection computer "SEES" full battery voltage all the time and cycling of injectors doesn't create an issue with the 'Sample' the alternator sees.

When injectors cycle, they case high/low voltage issues, and that will cause the alternator to cause 'Brown Outs' and Voltage Spikes.

When connected to the battery cable, the LARGE SUPPLY FROM THE BATTERY buffers those cycling issues and you have a lot less issues with the fuel injection and charging system.

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Quote:

Q3: solenoid has alt cable, and wiring harness on one end, then blue wire from harness on next terminal, then nothing, then black wire to starter. Correct? What is blank post for?

There are usually 4 posts,
1. Battery Cable
2. Starter Cable
3. 'S' or 'Start' terminal, the terminal that activates the relay to crank the starter,
4. 'I' or 'Ignition' terminal, and it was orignally there to power up the ignition while cranking.

Depending on how/where the 'I' terminal is wired, it was there to supply the ignition with power during cranking.
On some systems, it actually supplied full battery voltage to the ignition to get the engine running when cold and hard to fire...

Some fuel injection systems use it as a 'Cranking Trigger' signal to let the fuel injection know it's time for extra fuel ('Choke') when you first try to start.

In your case, since you don't report hard starting or long cranking times, it's probably not needed.

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Quote:

Q4: there is an extra module of wires that runs from efi relay and battery direct but just has unhooked wires. Is this the correct way to wire it?

No one can answer that without knowing what fuel injection you have and a picture or diagram of what you are talking about,
So if someone *Tries* to tell you different, I'd take that advise with a grain of salt or two...

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Quote:

If these are correct I can start tracing the drain and the light flickering issue ( would this have to do with heat since only occurs around town after 30 min)...

I've seen what you describe before, and it's *PROBABLY* two different issues...

Headlights...
I'd start with making sure the bulkhead connector is clean and tight,
I'd start with making sure the dimmer switch is working correctly and not corroded,
I'd start with checking to see if it's the breaker in the switch that is cycling, or some other part of the headlight wiring/lights are causing issues...

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Something no one ever discusses about fuel injection...
IT'S VERY VOLTAGE SENSITIVE!

Everyone *THINKS* that companies went back to the drawing board on alternators because they wanted more power at lower RPM...

That isn't true...

The 'Redesign' and large changes were mostly in voltage REGULATORS & RECTIFIERS, not the basic design of the alternator.

Fuel injection & ultra sensitive ignition modules came along, and there were all kinds of problems with the older alternators killing both sensitive components.

You don't have HUGE electrical loads with a CJ, so you don't need a huge output alternator like most guys think,
But you DO NEED ONE THAT WILL PUT CURRENT OUT THAT DOESN'T ADVERSELY AFFECT THE MORE SENSITIVE ELECTRONICS.

In particular, the OLDER GM SI series alternators had voltage spikes when they first started charging that played havoc with sensitive electronics.
If you have a GM alternator, it's best to use a CS series rather than an SI series...

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Until you do some tracking of the issues on there own, there isn't much we can do from here...

1. You need FIX what PO has done.
The smaller 'Red' wire to the battery needs to be attached to the battery cable side of the starter relay.

That wire MUST go to the 'Brass' post on the breaker,
And the 'Silver' or 'Steel' post on the breaker goes out to the accessory.

I can't tell in the picture if it's wired this way or not..

Jeephammer, thanks for the advice. Let me describe that breaker wiring: on the copper looking side there are two connections: on w fuse that goes to efi and one that goes to positive battery terminal. On the other silver side of the breaker there is a wire that goes to alt where smaller wires are joined together to that one and one that goes to an auxiliary fuse bank ( joined at bank with ground from neg terminal you see in pic).

Does that seem right to you?

Quote:

Originally Posted by JeepHammer

Where I would start,
There *Should* be two wires (About 10 Ga.) connected to the starter relay battery cable post.

One should be the alternator 'BAT' terminal,
The other should be the feed to the headlights/fuse block.
This will tell you right away if the drain is under the dash or the alternator..

With the starter relay there are the four posts. On the side near the battery there is a 10 gauge connection to the positive terminal of battery, one for main wiring harness and one 10 gauge to the alt.

Then on the first small post beside that there is a blue wire from Main harness. The next post has nothing and the back side away from firewall goes to starter (automatic transmission).

I apologize for being such a rookie but want to see if this is correct before I start tracing drain and headlights (thx for the tips there). J

You need to DISCONNECT either the positive or negative battery cable from the battery, and put a volt meter between cable and post.

This will let you track voltage drawn from battery with the key switch 'OFF'.
Start pulling fuses, disconnecting things until you find the drain,
Then address the drain issues.

You meant ammeter and current draw, correct? I know you did, I'm just clarifying so we are all on the same page. With all that you wrote I can see how it would be easy to make a typo.

No need to apologize, we were all rookies at some point. Since the jeep runs well enough to get you around town for two 30 minute trips I'd say the bigger issue you have is the parasitic drain and headlight problem. I'd be chasing those 1st.

Your EFI is a custom installation. It's going to be very difficult to tell you if it's wired correctly when we don't have any information about the system. We would need schematics of your EFI system if you have them.

Have you put a meter in series with the negative batt cable and even seen what current flow is? I recommend negative because if you were to touch the cable to ground anywhere it doesn't matter. However with the positive cable and under the right combination of things touching you are arcing.

Current flow is the same whether it's pos or neg batt cable, doesn't matter. So acquire an ammeter and see what the numbers are. If you see some current flowing start disco'ing these wires you are asking about and see if it stops. It's just that easy. Tell us what wire you disco'd to stop it and then we will try to help you figure out how it's wired wrong.